bug#20024: grub store is not copied to target system

[Tomáš Čech]

On Mon, Mar 09, 2015 at 06:00:24PM +0100, Ludovic Courtès wrote:
> Tomas Cech <address@hidden> skribis:
>
> > I'm afraid that I don't understand the relation between `guix system init' and
> > `guix system reconfigure' you insist on. My understanding was, that `guix
> > system init' will create new system in subdirectory as it is described in
> > manual (6.1.4 Proceeding with the Installation).
>
> ‘guix system init’ initializes a GuixSD root file system.  It is
> typically used from the USB installation image.
>
> Conversely, ‘guix system reconfigure’ is used to reconfigure an already
> installed GuixSD system, with the untold assumption that the root
> partition remains the same (which is reasonable, IMO.)

Thank you for your verification. It means I understand it correctly.

I reread whole bug again and I couldn't find the reason you even
consider me using `guix system reconfigure'. My assumption is that you
didn't expect me to have Guix on my Gentoo.

Guix is (as you have to know the best) non-intrusive for OS so I have
standard Gentoo installation and Guix built from GIT and installed to
system. Binaries are in /gnu/store so it is not colliding with the
rest of my system. I'll keep that in mind to mention it better in
future bugs. Sorry for confusion.

TL;DR
I run `guix system init' from Gentoo to separate partition to
_init_ root filesystem and after reboot to boot into GuixSD.

> > > Seriously, I don’t think we’d want it to automagically migrate the
> > > store.
> >
> > How does it differ from building new VM image?
>
> ‘init’ is similar to building a new VM image; ‘reconfigure’ is not.
>
> Specifically, ‘reconfigure’ changes things to have immediate effect,
> such as switching /run/current-system/ to the new (reconfigured) system.
> Eventually it will also offer to restart dmd services whose definition
> have changed.

I hope it is now obvious that I didn't `reconfigure', but `init'.

> > > Maybe it could check whether the root partition in the OS declaration is
> > > the same as the one that holds the current store, but I’m not sure if
> > > that can be done reliably.  Thoughts?
> >
> > Again, I'm afraid we misunderstood each other.
> >
> > One thing is that you can expose it to configuration and let user configure it
> > correctly. I was already thinking that I'm wasting disk space with two copies
> > of /gnu/store on my computer (on Gentoo and on GuixSD).
>
> Oh, I see.  So you had installed Guix atop Gentoo, and from there you
> wanted to install GuixSD while (1) keeping Gentoo, and (2) not
> rebuilding a new store, right?

Yes.

> The solution to is to run, from your Gentoo system:
>
>  # guix system init config.scm /
>
> The “/” here means that you keep the same root file system, and thus the
> same store.
>
> If you want to still be able to boot into Gentoo, you need to specify
> GRUB menu entries in config.scm, like
>
>  (define gentoo-entry
>    (menu-entry
>     (label "Gentoo")
>     (linux "/whatever/bzImage")
>     (linux-arguments '("answer=42"))
>     (initrd "/something/initrd.gz")))
>
>  (operating-system
>    ;; ...
>    (bootloader (grub-configuration
>                 (device "/dev/sda")
>                 (menu-entries (list gentoo-entry)))))

I'm aware of this feature, I'm preparing bug report for that :)

> But!  Beware that GuixSD wants to own /etc.  So in practice, when you
> boot GuixSD, it may override most of the files in there with its own (it
> might also bork of some of its assumptions do not hold, like if Gentoo
> left files in /etc that it doesn’t expect to see.)  So the next time you
> boot into Gentoo, Gentoo will basically be somewhat broken.
>
> IOW, using ‘guix system init’ on the current root should be thought of
> as a one-way transition.  It’s not documented because it’s brittle and
> it’s most likely not what you want.

Yes, that would be way to hell. So the better solution can be putting
/gnu on separate partition and share it among the systems like you can
do for /home, /boot etc.


> Does that better answer your questions?

Yes and no. I really appreciate your patience here but we diverged
from original reported issue.

Let me the whole bug rephrase into single simple question:

Shouldn't `grub' be in `%base-packages'?


Thanks and best regards,

S_W

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